(1) Field of the Invention
This invention relates to new oligopeptides compounds that demonstrate phytotoxic and plant growth regulating properties.
(2) Description of the Prior Art
The cyclic tetrapeptides HC toxin and tentoxin have been isolated from fungal culture filtrates, structurally characterized, and screened for their phytotoxic activities. Tentoxin which has the sequence cyclo [L-Leucyl-N-methyl-(Z)-dehydrophenylalanyl-glycyl-N-methyl-L-alnyl] was originally isolated from fungal culture filtrates of Alternaria tenuis and described as a non-host specific toxin [Meyer, W. L.; Kuyper, L. F., Lewis, R. B., Templeton, G. E. and Woodhead S. H., Biochem Biophys. Res. Comm. 56: 234-240 (1974)]. Biologically, tentoxin induces chlorosis in lettuce, potato, cucumber and spinach but not in radish, corn and some species of tobacco. This biological activity has been directly correlated with the conformation of the cyclic tetrapeptide, (Rich, D. H. and Bhatnagar, P. K., J. Am. Chem. Soc. 100:7, 2212-2218. Kato, T., Tone A., Kodera, Y., Lee, S., Shimohigashi, Y., and Izumiya, N., Chemistry Letters, pp. 1209-1212, 1985. HC toxin, which has the sequence cyclo [L-2-amino-9-10-epoxy-8-oxo-decanoyl)-D-prolyl-L-alanyl-alanyl] was originally isolated as a host-specific toxin from Helminthosporium carbonum [J. D. Walton, Elizabeth D. Earle, and Bradford W. Gibson, Biochem. Biophys. Res. Comm., 107: 785 , (1982)] and biologically characterized for its root growth inhibition of susceptible maize hybrids.